1243509149 has 16 divisors (see below), whose sum is σ = 1328388336. Its totient is φ = 1159987200.

The previous prime is 1243509121. The next prime is 1243509187. The reversal of 1243509149 is 9419053421.

It can be written as a sum of positive squares in 8 ways, for example, as 710222500 + 533286649 = 26650^2 + 23093^2 .

It is a cyclic number.

It is not a de Polignac number, because 1243509149 - 2²⁰ = 1242460573 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243509109) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1052339 + ... + 1053519.

It is an arithmetic number, because the mean of its divisors is an integer number (83024271).

Almost surely, 2^1243509149 is an apocalyptic number.

It is an amenable number.

1243509149 is a deficient number, since it is larger than the sum of its proper divisors (84879187).

1243509149 is a wasteful number, since it uses less digits than its factorization.

1243509149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1696.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 1243509149 is about 35263.4250888934. The cubic root of 1243509149 is about 1075.3495597297.

The spelling of 1243509149 in words is "one billion, two hundred forty-three million, five hundred nine thousand, one hundred forty-nine".